That argument has gone back and forth since the dawn of the space age. Both the US and USSR had plans to go to the Moon using smaller launchers, and rendezvousing in LEO.
I'll just say, that the big launch method has worked a couple of times. The lots of little launches method has yet to work at all.
Obviously, a US news source is going to use the largest NASA rocket ever flown as the basis for comparison, but I think their option 'A' design looks quite like the Soviet Energiya booster.
Saturn V was a single body launch vehicle - each stage was stacked on top of each other, and fired sequentially. This was simpler to assemble, but meant that two stages had to start in flight - one of which had to start twice! The first stage was LOx/RP-1 to get high thrust low in the Earth's atmosphere, and the upper stages were LOx/LH2 to get maximum delta-V.
Energiya, on the other hand, looked more like the US shuttle stack (and indeed, was used to fly the Soviet version of the space shuttle, the main difference being its ability to fly without the shuttle as its own rocket). It had a LOx/LH2 core stage, surrounded by 4 LOx/RP-1 boosters. All of the engines were started on the ground, at liftoff. Energiya was a mode 'modern' super heavy launch vehicle, as this approach is widely considered better these days.
Sensibly, the Chinese appear to have looked to the most recent super heavy (100t+ payload capacity) launch vehicle that successfully flew for design cues.
Violently assaulting someone is the French equivalent of the waiter coming over and asking 'is everything alright with your meal?'. It very slightly more irritating too.
It isn't that hard to design a system that is passively thermal managed, for a realistic range of spin rates.
The mounting points is a serious stumbling block; certainly moreso than radiation or temperature. Launch vehicles that don't have squishy human payloads aren't shy about peaking at 15Gs (SD cards can and should be glued in place. We already investigated this.) I never did mechanical design - but unless I hear otherwise I wouldn't consider it a fatal problem. If thermal and mounting do become really problematic - then yes, it might be worth creating a flight board. The only advantage then is the familiarity of the platform - but having tried to get undergraduates to program a microcontroller for the last project, that is likely a big advantage.
Power is an issue. A 1U cubesat can expect about 2W continuous, about half of which you lose straight away charging the batteries that keep you alive during eclipse. At a push you can put it into a lower power mode for eclipse, so long as that doesn't compromise your science goals. Most likely the Pi is going to fly in a 3U satellite.
It is a big technical challenge, but the nice thing is that you get a technical continuum between first learning to code at school, through to simpler projects such as robots and balloons - and then to a space project. All under the same architecture. Whilst it not ultimately be the best space hardware, its a pretty good teaching tool.
Why can't you use Raspberry Pi (or other COTS electronics) in space? Just because radiation and heat are issues, does not mean they are automatically terminal issues.
A little knowledge is a dangerous thing. Yes, thermal control is a problem. No, it is not a showstopper that stops you using COTS electronics in space.
Wrong guess about the board, and wrong about everything else too. No wonder you are posting as AC. We have investigated the use of phones for this application before (because we are not stupid) but found several problems.
I'm not going to get into this because you seem like a troll, and it probably isn't worth my time engaging with someone using anonymity to snarl at someone across the Internet. Bye.
Don't have them to hand, but we were modelling a much lower orbit (few hundred kms) which makes a big difference for radiation. We look at COTS survivability for a year, at 45 degree inclination, and found it good enough for student work:)
The exceptional point about the Raspberry Pi is that you can get undergraduates to program it well within the timescale of a degree. That team from Leicester University that is mentioned in the article? I'm part of it:
http://edgepenguin.com/content/raspberry.html
One of the issues we had in a previous (abandoned) cubesat project was the difficulty in programming a microcontroller.
Having been part of an attempt to construct a cubesat, I can confidently assert that you are talking BS. Costs for cubesats are in equipment - because most of them are assembled by students who volunteer, and you don't have any labour costs with them. The difference between the cost of a Pi and the previous board we used is not small change. It was about 10% of the launch cost, and the single largest item we purchased before the project was cancelled.
Radiation hardening is an issue - but not one that will kill a mission. This appears to be a mount stupid effect; some people know there is radiation in space, and that it can effect electronics - and therefore jump to "omg any non-hardened chip will day within days! Don't you know anything!?" - despite not knowing the details of how COTS interacts with the LEO radiation environment.
Radiation in LEO isn't that bad. COTS components don't just die the moment they leave the atmosphere. If every single event upset translated into an actual fault, they wouldn't be very reliable down here on earth either.
Cubesats have flown with COTS hardware - and they have done it through orbits that pass through the south atlantic anomaly. Yes, there are reliability issues - but certainly not showstoppers.
So, you are saying a Nature page on AGW overreaches a bit with its conclusion, and The Register then runs with this as the definitive proof that ALL CLIMATE CHANGE IS FALSE?
Googling someone does not violate their privacy. Publishing unauthorized information about someone does.
The whole thing is daft and bound to backfire. For instance; I share my name (which you can easily figure out from my username) with a purveyor of adult photography. I don't want airport staff casually inquiring how the porn business is going.
It is special because they really need to dump the last generation computer off on somebody so they can afford to run the new one. STFC has just paid for some new computers for physics, and one of them is in Cambridge. What they haven't done (at least here in Leicester) is paid for the electricity.
Basically this is universities holding an electronic car boot sale because they are down on funding.
Yes, in the past the BBC has gone against the government (Christine Hamilton, wife of a prominent Tory, said it stood for Buggars Broadcasting Communism, but then again she is a stupid bitch) - but it has been defanged ever since it reported (correctly) that the Dodgy Dossier was a load of BS, but weren't able to back up their reporting to the standard a government inquiry demanded. Its worth noting, that the outright fabrications in the dossier were subject to no such official scrutiny. Since then, the BBC has been much more careful, and much less willing to take the government to task.
Its only a little space station, and its only a docking. Yes, the US did all this years ago. But what have you done since?
Whatever else you may think of the Chinese government, it's manned space program is excellent. Despite a low launch rate, it is inaccurate to describe it as slow. Each individual mission is a significant step forwards, whereas in the comparable stage in the US/Soviet space race, large numbers of similar missions were being flown.
They are being methodical and efficient. Every mission they launch is a clear and useful step towards their first major stated objective (an orbiting space station). Look at Tiangong 1 - despite its space lab moniker, its main role is as a docking target - comparable to the 'Agena' docking target of the Gemini project. Except that Tiangong 1 is dual use; loaded up with supplies, versions of it will be used as a cargo ferry to future Chinese space stations. Tiangong 1 itself is closely derived from the Shenzhou spacecraft, so they have greatly reduced the cost of developing a large cargo transport by piggy-backing it on the development and testing they would have to do for Shenzhou anyway.
China is only 'behind' in the list of things they've done in space, and are rapidly catching up. They have the technological base (largely thanks to US outsourcing manufacturing there) and they have a political culture which is patient and long term.
Contrast this to the US; the post Apollo era is characterized by presidents dreaming up the next big thing, and then having it cancelled or underfunded by later presidents (Nixon had the Shuttle, Reagan has "Space Station Freedom", Bush I had the 90 day study, Bush II had VSE, and now Obama has COTS and SLS - both might not survive the next guy)
If the US picked a program, funded it properly, and stuck with it - then its head start and technological know-how would leave China in the dust. But really, what is the chance of that actually happening? This is the view of a foreigner, but most US politics seems to centre around endless, futile, partisan bickering. Whence the political will for a long term, bi-partisan space program that presidents can resist the urge to constantly meddle with and reorganise?
The crew of Soyuz 11 were killed by a depressurization accident that occurred during undocking (I believe the separation of one part of the Soyuz capsule from another) and the collision of a Progress craft with Mir caused a loss of pressure. Wearing spacesuits when you are doing docking stuff is a very good idea.
After Planetary Resources was launched, I blogged about potential issues of who gets what in space:
http://edgepenguin.com/content/asteroid.html
TLDR version; I am not sure that there will be enough public money to create the demand needed to make asteroid mining work, but it will probably open a can of worms regarding who owns stuff in space, and if it isn't sorted out amicably, everyone will get screwed by space war and the resulting Kessler syndrome.
Or, to put it another way, how little the Chinese are investing. The space program is clearly not viewed as a high economic priority in China. The period between their first manned flight and now is roughly the same as the period between the first US manned flight and first US lunar landing; and in that time period China has had an economy far in excess of that of the US in the 1960s. They have also had lower costs due to the fact that they don't have to develop all the technology from scratch. They could easily have done a repeat of Apollo on this time scale, but chose not to.
Given your sig, you aren't in the best position to comment on other peoples science illiteracy. Thinking that you are 'smart' enough to believe that dark matter is some kind of fudge or hoax is simply a more high-brow version of creationism; look at the scientific consensus, decide that you've more common sense than these eggheads, and unilaterally decide how you think nature works without any evidence.
Which is kind of what you do with the survey data to. You decide the pollsters don't know what they are doing, throw away their evidence, and declare the 'truth' without any evidence at all. How is this better than creationism?
That is capitalism for you; everything is margins, and margins are dependent on costs. Aside from well known premium brands that can charge high price (e.g. Apple) everyone makes money by trying to provide the absolute worst serivce that won't make you jump ship and take another supplier.
Surely they need to investigate libertarian bias (especially seeing as Wales himself is, how should I put this, a raving Objectivist nutjob). The fact that libertarian beliefs overlap with democrat and republican beliefs can explain the two separate slants with one single hypothesis.
Indeed; I should imagine that those who fought against Franco in the Spanish Civil War have little in common with Newt Gingrich and Mitt Romney, and neither have much in common with the former Iraqi Republican guard.
Slashdot Mirror
That argument has gone back and forth since the dawn of the space age. Both the US and USSR had plans to go to the Moon using smaller launchers, and rendezvousing in LEO.
I'll just say, that the big launch method has worked a couple of times. The lots of little launches method has yet to work at all.
Obviously, a US news source is going to use the largest NASA rocket ever flown as the basis for comparison, but I think their option 'A' design looks quite like the Soviet Energiya booster.
Saturn V was a single body launch vehicle - each stage was stacked on top of each other, and fired sequentially. This was simpler to assemble, but meant that two stages had to start in flight - one of which had to start twice! The first stage was LOx/RP-1 to get high thrust low in the Earth's atmosphere, and the upper stages were LOx/LH2 to get maximum delta-V.
Energiya, on the other hand, looked more like the US shuttle stack (and indeed, was used to fly the Soviet version of the space shuttle, the main difference being its ability to fly without the shuttle as its own rocket). It had a LOx/LH2 core stage, surrounded by 4 LOx/RP-1 boosters. All of the engines were started on the ground, at liftoff. Energiya was a mode 'modern' super heavy launch vehicle, as this approach is widely considered better these days.
Sensibly, the Chinese appear to have looked to the most recent super heavy (100t+ payload capacity) launch vehicle that successfully flew for design cues.
Well, that might not be impossible http://www.reactionengines.co.uk/
Violently assaulting someone is the French equivalent of the waiter coming over and asking 'is everything alright with your meal?'. It very slightly more irritating too.
It isn't that hard to design a system that is passively thermal managed, for a realistic range of spin rates.
The mounting points is a serious stumbling block; certainly moreso than radiation or temperature. Launch vehicles that don't have squishy human payloads aren't shy about peaking at 15Gs (SD cards can and should be glued in place. We already investigated this.) I never did mechanical design - but unless I hear otherwise I wouldn't consider it a fatal problem. If thermal and mounting do become really problematic - then yes, it might be worth creating a flight board. The only advantage then is the familiarity of the platform - but having tried to get undergraduates to program a microcontroller for the last project, that is likely a big advantage.
Power is an issue. A 1U cubesat can expect about 2W continuous, about half of which you lose straight away charging the batteries that keep you alive during eclipse. At a push you can put it into a lower power mode for eclipse, so long as that doesn't compromise your science goals. Most likely the Pi is going to fly in a 3U satellite.
It is a big technical challenge, but the nice thing is that you get a technical continuum between first learning to code at school, through to simpler projects such as robots and balloons - and then to a space project. All under the same architecture. Whilst it not ultimately be the best space hardware, its a pretty good teaching tool.
Why can't you use Raspberry Pi (or other COTS electronics) in space? Just because radiation and heat are issues, does not mean they are automatically terminal issues.
A little knowledge is a dangerous thing. Yes, thermal control is a problem. No, it is not a showstopper that stops you using COTS electronics in space.
Wrong guess about the board, and wrong about everything else too. No wonder you are posting as AC. We have investigated the use of phones for this application before (because we are not stupid) but found several problems.
I'm not going to get into this because you seem like a troll, and it probably isn't worth my time engaging with someone using anonymity to snarl at someone across the Internet. Bye.
Don't have them to hand, but we were modelling a much lower orbit (few hundred kms) which makes a big difference for radiation. We look at COTS survivability for a year, at 45 degree inclination, and found it good enough for student work :)
Wrong.
The exceptional point about the Raspberry Pi is that you can get undergraduates to program it well within the timescale of a degree. That team from Leicester University that is mentioned in the article? I'm part of it:
http://edgepenguin.com/content/raspberry.html
One of the issues we had in a previous (abandoned) cubesat project was the difficulty in programming a microcontroller.
Having been part of an attempt to construct a cubesat, I can confidently assert that you are talking BS. Costs for cubesats are in equipment - because most of them are assembled by students who volunteer, and you don't have any labour costs with them. The difference between the cost of a Pi and the previous board we used is not small change. It was about 10% of the launch cost, and the single largest item we purchased before the project was cancelled.
Radiation hardening is an issue - but not one that will kill a mission. This appears to be a mount stupid effect; some people know there is radiation in space, and that it can effect electronics - and therefore jump to "omg any non-hardened chip will day within days! Don't you know anything!?" - despite not knowing the details of how COTS interacts with the LEO radiation environment.
Got any evidence to back that up? Have you actually modeled COTS components in the radiation environment of LEO? I have.
Radiation in LEO isn't that bad. COTS components don't just die the moment they leave the atmosphere. If every single event upset translated into an actual fault, they wouldn't be very reliable down here on earth either.
Cubesats have flown with COTS hardware - and they have done it through orbits that pass through the south atlantic anomaly. Yes, there are reliability issues - but certainly not showstoppers.
So, you are saying a Nature page on AGW overreaches a bit with its conclusion, and The Register then runs with this as the definitive proof that ALL CLIMATE CHANGE IS FALSE?
None of this is a massive shock to me.
Googling someone does not violate their privacy. Publishing unauthorized information about someone does.
The whole thing is daft and bound to backfire. For instance; I share my name (which you can easily figure out from my username) with a purveyor of adult photography. I don't want airport staff casually inquiring how the porn business is going.
It is special because they really need to dump the last generation computer off on somebody so they can afford to run the new one. STFC has just paid for some new computers for physics, and one of them is in Cambridge. What they haven't done (at least here in Leicester) is paid for the electricity.
Basically this is universities holding an electronic car boot sale because they are down on funding.
Yes, in the past the BBC has gone against the government (Christine Hamilton, wife of a prominent Tory, said it stood for Buggars Broadcasting Communism, but then again she is a stupid bitch) - but it has been defanged ever since it reported (correctly) that the Dodgy Dossier was a load of BS, but weren't able to back up their reporting to the standard a government inquiry demanded. Its worth noting, that the outright fabrications in the dossier were subject to no such official scrutiny. Since then, the BBC has been much more careful, and much less willing to take the government to task.
Its only a little space station, and its only a docking. Yes, the US did all this years ago. But what have you done since?
Whatever else you may think of the Chinese government, it's manned space program is excellent. Despite a low launch rate, it is inaccurate to describe it as slow. Each individual mission is a significant step forwards, whereas in the comparable stage in the US/Soviet space race, large numbers of similar missions were being flown.
They are being methodical and efficient. Every mission they launch is a clear and useful step towards their first major stated objective (an orbiting space station). Look at Tiangong 1 - despite its space lab moniker, its main role is as a docking target - comparable to the 'Agena' docking target of the Gemini project. Except that Tiangong 1 is dual use; loaded up with supplies, versions of it will be used as a cargo ferry to future Chinese space stations. Tiangong 1 itself is closely derived from the Shenzhou spacecraft, so they have greatly reduced the cost of developing a large cargo transport by piggy-backing it on the development and testing they would have to do for Shenzhou anyway.
China is only 'behind' in the list of things they've done in space, and are rapidly catching up. They have the technological base (largely thanks to US outsourcing manufacturing there) and they have a political culture which is patient and long term.
Contrast this to the US; the post Apollo era is characterized by presidents dreaming up the next big thing, and then having it cancelled or underfunded by later presidents (Nixon had the Shuttle, Reagan has "Space Station Freedom", Bush I had the 90 day study, Bush II had VSE, and now Obama has COTS and SLS - both might not survive the next guy)
If the US picked a program, funded it properly, and stuck with it - then its head start and technological know-how would leave China in the dust. But really, what is the chance of that actually happening? This is the view of a foreigner, but most US politics seems to centre around endless, futile, partisan bickering. Whence the political will for a long term, bi-partisan space program that presidents can resist the urge to constantly meddle with and reorganise?
The crew of Soyuz 11 were killed by a depressurization accident that occurred during undocking (I believe the separation of one part of the Soyuz capsule from another) and the collision of a Progress craft with Mir caused a loss of pressure. Wearing spacesuits when you are doing docking stuff is a very good idea.
These things happens to empires. Don't worry, as a Brit I can assure you there is life after world domination.
After Planetary Resources was launched, I blogged about potential issues of who gets what in space:
http://edgepenguin.com/content/asteroid.html
TLDR version; I am not sure that there will be enough public money to create the demand needed to make asteroid mining work, but it will probably open a can of worms regarding who owns stuff in space, and if it isn't sorted out amicably, everyone will get screwed by space war and the resulting Kessler syndrome.
Or, to put it another way, how little the Chinese are investing. The space program is clearly not viewed as a high economic priority in China. The period between their first manned flight and now is roughly the same as the period between the first US manned flight and first US lunar landing; and in that time period China has had an economy far in excess of that of the US in the 1960s. They have also had lower costs due to the fact that they don't have to develop all the technology from scratch. They could easily have done a repeat of Apollo on this time scale, but chose not to.
Given your sig, you aren't in the best position to comment on other peoples science illiteracy. Thinking that you are 'smart' enough to believe that dark matter is some kind of fudge or hoax is simply a more high-brow version of creationism; look at the scientific consensus, decide that you've more common sense than these eggheads, and unilaterally decide how you think nature works without any evidence.
Which is kind of what you do with the survey data to. You decide the pollsters don't know what they are doing, throw away their evidence, and declare the 'truth' without any evidence at all. How is this better than creationism?
That is capitalism for you; everything is margins, and margins are dependent on costs. Aside from well known premium brands that can charge high price (e.g. Apple) everyone makes money by trying to provide the absolute worst serivce that won't make you jump ship and take another supplier.
Surely they need to investigate libertarian bias (especially seeing as Wales himself is, how should I put this, a raving Objectivist nutjob). The fact that libertarian beliefs overlap with democrat and republican beliefs can explain the two separate slants with one single hypothesis.
Indeed; I should imagine that those who fought against Franco in the Spanish Civil War have little in common with Newt Gingrich and Mitt Romney, and neither have much in common with the former Iraqi Republican guard.